The present invention relates to an access- and starting/driving-authorization system for a motor vehicle, having a portable transponder and a control unit, which is accomodated in the motor vehicle and is for the smart master-key system and the engine control unit; in inquiry/response dialogs using sets of code information matched to each other, the transponder and the control unit enabling or blocking access to the motor vehicle, and the starting and driving of the motor vehicle.
Many different transponder and control-unit designs based on different transmission methods are known for such authorization systems. For accessing, or for starting and driving, both the control units and the inquiry/response dialogs function, as a rule, independently of one another, and use different sets of code information. However, this has the disadvantage, that the motor vehicle can be started and driven when the motor vehicle is forcibly entered, and the engine control unit having a transponder-controlled vehicle immobilizer is replaced with another engine control unit having a transponder matched to it. Therefore, the starting/driving-authorization system is not reliable when the motor vehicle is forcibly entered and the engine control unit is replaced.
As is indicated in German Patent No. 44 03 655 C2, it is also known that the access-authorization inquiry/response dialog can be used, not only to unlock and lock the smart master-key system, but also to simultaneously activate an additional control unit that enables or disables the engine starting system. The starting and driving operation of the motor vehicle is initiated in a known manner, e.g. by a starter switch.
The object of the present invention is to considerably improve an access- and starting/driving-authorization system of the type mentioned at the outset, in its protection against unauthorized replacement of the engine control unit and the access control system.
This object is achieved in accordance with the present invention, in that the enabling of the starting and the driving of the motor vehicle after a successful starting/driving-authorization inquiry/response dialog is rendered dependent on a preceding access-authorization inquiry/response dialog being successful.
In this context, the improved starting/driving-authorization system requires proper access to the motor vehicle beforehand, which is only possible using the transponder matched to the built-in access authorization. Having a new engine control unit and the matching transponder is not sufficient for starting and driving the motor vehicle after forcibly entering it and replacing the engine control unit. The access-authorization system and the starting/driving-authorization system are compulsorily coupled, which considerably increases the reliability.
The access-authorization system functions in a simple manner, in that the initiation of the access-authorization inquiry/response dialog at the control unit is dependent on an initialization signal, which is triggerable by a manual switching measure at the motor vehicle or a manual switching measure at the transponder; or in that the initiation of the access-authorization inquiry/response dialog is rendered dependent on the presence of the transponder in a field of the motor vehicle monitored by a proximity switch in the motor vehicle. The operation of a door handle or the like is preferably used as a switching measure at the motor vehicle. When a proximity switch is present, it determines if a person is in the monitored field of the motor vehicle. If so, then an access-authorization inquiry signal of the control unit is triggered, which can only be responded to correctly when this person is carrying the appropriate transponder with himself or herself.
According to the present invention, the method for the starting/driving-authorization system after a successful access-authorization inquiry/response dialog is such, that the access control unit initiates the unlocking of the smart master-key system after a successful access-authorization inquiry/response dialog, and holds a set of additional information in readiness for the subsequent starting/driving-authorization inquiry/response dialog.
In accordance with a development of the starting/driving-authorization system, it is provided that the initiation of the starting/driving-authorization inquiry/response dialog be rendered dependent on putting the transponder down in a storage box in the motor vehicle, or be rendered dependent on another initialization signal, which is triggered in the motor vehicle, and is for the control unit functionally assigned to the starting/driving authorization. According to this method, in response to a successful starting/driving-authorization inquiry/response dialog, the engine control unit is only triggered to enable starting and driving when a set of enabling, additional information is present from the previous access-authorization inquiry/response dialog.
The protection against unauthorized starting and driving of the motor vehicle can be further increased by additionally rendering the enabling of the starting and driving of the motor vehicle dependent on the output state of the smart master-key system, or by incorporating predefined states and/or operating sequences of other vehicle components, in order to enable the motor vehicle to be started and driven.
In addition to the engine control unit, it is especially advantageous when other components required for starting and driving a motor vehicle, e.g. the transmission control system, are enabled for starting and driving, by means of the set of additional information transmitted to these components by the respective control unit, after the access inquiry/response dialog has been carried out successfully.
Using a set of additional information, which is acquired and stored in the control unit after properly locking the vehicle, and is routed to all of the incorporated components, and after disconnecting the supply/operating voltage of the incorporated components, the particular control unit, as well as the engine control unit and all other components incorporated in the system designed according to the present invention, are brought into a functionally disabled state, which can only be cancelled by the set of additional information present after correctly accessing the vehicle. This renders exchanged/removed components unusable as replacement parts, which considerably reduces the incentive to steal.
An advantageous refinement of the present invention provides a single control unit in place of separate control units for the access control and the starting/driving-authorization control. However, these two objectives can also be fulfilled by another control unit already existing for other purposes, e.g. the engine control unit, by appropriately expanding its function.
An advantageous refinement of the present invention provides for the transponder, control unit, engine control unit, and other operationally relevant components being coded on the manufacturing end, at the vehicle manufacturer. Components that are not coded due to being improperly exchanged are detected by the other components, thereby leading to inoperativeness. Specially protected authorization tables provided with the appropriate authorization (e.g. xe2x80x9cRed Keyxe2x80x9d, master transponder, etc.) are necessary for coding.
The link according to the present invention, between the locking system and the vehicle immobilizer or engine control unit, for the purpose of exchanging data, provides the additional advantage that, in response to advantageously internal actuating elements of the locking system being operated in an unlocked motor vehicle, in a manner deviating from normal operation, a forcible removal of the vehicle (xe2x80x9ccar-nappingxe2x80x9d) can be registered, whereupon the operationally relevant control units of the motor vehicle only allow the motor vehicle to be driven a short distance before they shut themselves down entirely, and therefore shut the motor vehicle down. After an erroneous instance of triggering, the granted path of travel either allows the driver to get out of danger or, after having to leave the vehicle, to remove himself from a threatening situation or, given the possibility that the criminal(s) can temporarily escape with the forcibly removed motor vehicle, to no longer be threatened. For example, operating the inner door handle repeatedly (preferably that of the driver""s door) can be used as a trigger, since this handle is also normally used when getting out, and the emergency signalling can be concealed.